Stratified, randomized, double-blind comparison of intravenous ondansetron administered as a multiple-dose regimen versus two single-dose regimens in the prevention of cisplatin-induced nausea and vomiting

Assessment of chemotherapy-induced emesis and evaluation of a reduced-dose intravenous ondansetron regimen in pediatric outpatients with leukemia

OBJECTIVE

To measure the severity of nausea and vomiting in pediatric patients receiving intravenous or intrathecal chemotherapy for acute lymphoblastic leukemia and to evaluate the effectiveness of 2 intravenous doses of ondansetron for this condition.

DESIGN

Patients were surveyed during repeated treatments of maintenance chemotherapy, given with or without ondansetron, using a repeated measures pretest/posttest design.

SETTING

Outpatient pediatric oncology clinic.

PATIENT POPULATION

Sixteen pediatric patients (aged 2-15 years, mean 6.2) with acute lymphoblastic leukemia.

METHODS

Surveys to assess nausea and vomiting and the extent of interference with daily activities were administered following emetogenic chemotherapy with or without ondansetron.

RESULTS

A total of 255 surveys following emetogenic chemotherapy with daunorubicin, cyclophosphamide, carmustine, and etoposide and cytarabine combined, as well as intrathecal therapy with methotrexate, hydrocortisone, and cytarabine, were analyzed. Analysis was performed on surveys of 149 courses without antiemetic therapy and 106 courses after 2 doses of ondansetron 0.15 mg/kg iv. The most emetogenic chemotherapy treatment was the etoposide/cytarabine combination (p < 0.05). Ondansetron completely protected patients (defined as no nausea or no vomiting) during most (> 50%) of the chemotherapy treatments, except for those in which cyclophosphamide was used. Ondansetron provided greater control of nausea and vomiting, a higher percentage of complete protection, and decreased the daily activity interference rating for carmustine and etoposide/cytarabine compared with courses of chemotherapy without antiemetics (p < 0.05). Two intravenous doses of ondansetron also provided durable antiemetic efficacy over time for the most emetogenic chemotherapy treatment (etoposide/cytarabine).

CONCLUSIONS

Etoposide/cytarabine proved to be the most emetogenic of the chemotherapy treatments studied. A reduced-dose regimen of intravenous ondansetron was shown to be an effective antiemetic for the outpatient treatments with etoposide/cytarabine and carmustine, but not with cyclophosphamide.

Antiemetics in children receiving cancer chemotherapy

Nausea and vomiting are debilitating side effects that often accompany the administration of chemotherapy and may lead to adverse physiological and psychological effects. Chemotherapy agents usually stimulate the chemoreceptor trigger zone, which then sends signals to the vomiting center in the medullary lateral reticular formation. The neurochemistry of vomiting involves serotonin and serotonin S3 receptors. Nausea and vomiting are difficult to treat once they have occurred, and prior poor antiemetic control may lead to future anticipatory nausea and vomiting. Thus, good antiemetic regimens must be prophylactic, scheduled, and individualized. Specific regimens must be adjusted to account for the emetogenic potential of the chemotherapy drug(s) being administered and the individual patient's preferences. The major classes of antiemetics include serotonin S3 receptor antagonists, phenothiazines and metoclopramide. Steroids are ineffective antiemetics alone but good potentiators of other antiemetics. We usually recommend a serotonin S3 receptor antagonist alone for less emetogenic regimens or in conjunction with dexamethasone for more emetogenic regimens. For breakthrough vomiting, we usually add lorazepam and/or scopolamine.

Are there differences among the serotonin antagonists?

The serotonin-receptor (5-HT3) antagonists combined with dexamethasone are considered the antiemetic therapy of choice in the prevention of cisplatin-induced emesis. As there are now several compounds on the market, the dilemma of preference is particularly relevant. In preclinical studies some differences among the three marketed drugs (ondansetron, granisetron and tropisetron) have emerged. In particular, tropisetron and granisetron have a greater potency and duration of action and seem to have a greater selectivity toward the 5-HT3 receptor with respect to ondansetron. Furthermore, while with tropisetron and granisetron there is a linear dose/response relationship, this does not seem to be the case for ondansetron. These preclinical differences, however, do not seem to correlate with the clinical antiemetic activity of these compounds. In fact, although the number of comparative studies is small, with all of them presenting several shortcomings (small number of patients, not blinded studies, no association with steroids, sponsored trials), it seems that the antiemetic activity and tolerability of ondansetron, granisetron and tropisetron is very similar. If these data are confirmed, the least expensive of the 5-HT3 antagonists should be the drug of choice. We feel, however, that the answer to this rather difficult question of choice will come from very large, independent, methodologically correct studies designed to show small but clinically significant differences (i.e., less than 10% in complete protection from emesis). These trials, which require about 1000-1500 patients, are ongoing and the one carried out as a multicenter study by the Italian Group for Antiemetic Research is close to conclusion.

Treatment of chemotherapy-induced emesis in the 1990s: impact of the 5-HT3 receptor antagonists

Considerable progress has been made in the development of means to limit nausea and vomiting arising from cancer chemotherapy. A number of key conceptual advances in the last decade have been critically important. these include recognition of the value of combination antiemetic therapy, identification of important patient- and treatment-related factors predictive of emesis, and appreciation of the importance of serotonin (5-HT) in the pathophysiology of emesis and the value of selective antagonists of the type-3 serotonin receptor. Comparative trials of the 5-HT3 receptor antagonists and classic antiemetic agents have helped define optimal antiemetic approaches in a number of settings. A combination of a 5-HT3 antagonist and dexamethasone is the treatment of choice for patients receiving single- and multiple-day cisplatin. The 5-HT3 antagonists are also effective agents with noncisplatin chemotherapy. Clear-cut superiority to classic antiemetics such as dexamethasone has not been consistently demonstrated, however. Results with the 5-HT3 antagonists in cisplatin-induced delayed emesis have been disappointing to date. The results of ongoing prospective trials should define their role more clearly. At present a combination of metoclopramide and dexamethasone is the treatment of choice in this setting. Results of trials comparing 5-HT3 antagonists are beginning to emerge. Available information suggests no clinically relevant differences in antiemetic efficacy between these agents. Many questions regarding the optimal use of the 5-HT3 antagonists and their integration into clinical practice remain unanswered and are the appropriate focus for additional study.

Control of Emesis by a Low Dose of Ondansetron and Dexamethasone

Aims and background

Ondansetron, a selective serotonin type 3 receptor antagonist, has been investigated at a wide range of doses. Recent studies have demonstrated that a single dose of this drug is active, either by intravenous bolus or continuous infusion. The main aim of this study was to evaluate the efficacy of a low dose of ondansetron in a simple and feasible schedule as follows: ondansetron 8 mg i.v. and dexamethasone 8 mg i.v. given before chemotherapy on day 1. Oral ondansetron 8 mg was subsequently given in the evening of day 1, and then even 12 hours on days 2, 3 and 4.

Methods

Forty-chemotherapy-naive patients receiving cisplatin, dacarbazine or other emetogenic drugs were enrolled in the study. All courses of chemotherapy were given in an outpatient setting.

Results

During the first cycle, complete control of acute emesis was achieved in 88% of cases, and no delayed emesis was recorded in 76%; acute and delayed nausea were absent in respectively 78% and 69% of cases. During the second, third and fourth cycles complete control of acute emesis was achieved in respectively 92%, 80% and 86% of cases, and no delayed emesis was recorded in 71%, 82% and 82%. No severe adverse effects were observed.

Conclusions

Our study shows that a single intravenous administration of low-dose ondansetron combined with intravenous dexamethasone and followed by oral ondansetron twice daily is effective in controlling emesis in patients receiving chemotherapy, and that it is feasible as an ambulatory regimen.

[Antiemetic treatment and chemotherapy: general review]

Chemotherapy-induced nausea and emesis are frequent and patients fearful. Emesis caused by cytotoxic agents can be related to their effects on central chemoreceptor or on the gut chemoreceptor by serotonin. 5HT3 receptor antagonists produce a major improvement in the control of cisplatin induced-emesis (70 to 80% of patients). The 5HT3-antagonist efficacy is significantly better than metoclopramide alone, or antimemetic combinations in highly emetogenic chemotherapy regimens but less good in moderately emetogenic chemotherapy. Studies with 5HT3 receptor antagonist plus corticosteroids show advantage over 5HT3 antagonist alone. Comparison studies between the different setrons didn't show any significant difference. Anticipary emesis are treated with anxiolytic drugs. The prevention of delayed emesis, not yet well controlled by 5HT3 antagonist, is a great therapeutic deal. Finally, some therapeutic problems are not resolved: minimal dose, use of oral route, efficacy in fractionated chemotherapy, treatment after loss of efficacy of 5HT3 antagonist.

Enhancing the effectiveness of the specific serotonin antagonists. Combination antiemetic therapy with dexamethasone

Combinations of drugs have become standard therapy for the prevention of vomiting caused by anticancer drugs like cisplatin. Recently, a new class of antiemetic agents, the potent and specific 5-HT3 receptor antagonists such as ondansetron, granisetron, and tropisetron, have been shown to be more effective and better tolerated than metoclopramide. This report describes the rationale for combination antiemetic therapy, details the testing of metoclopramide-based regimens as a model for combination therapy development, reviews completed trials of ondansetron plus dexamethasone, and offers strategies to further alleviate vomiting during anticancer chemotherapy. The reported trials testing metoclopramide-based combinations were reviewed and that experience was applied to the ongoing studies of ondansetron when used with dexamethasone and other agents. Combinations of metoclopramide, dexamethasone, and lorazepam prevented acute emesis caused by high-dose cisplatin in 63% of patients, lessened side effects, and were convenient enough to administer to outpatients. Completed trials of ondansetron and dexamethasone demonstrated improved vomiting control over ondansetron alone while using less cumbersome schedules. Attempts to improve ondansetron-based antiemetic regimens by developing optimal drug doses and schedules and adding adjuvant and different classes of antiemetic agents are now in clinical testing. Based on previous experience and current results, combinations of a specific serotonin agonist and dexamethasone are the best treatment for prevention of vomiting induced by chemotherapy. Future clinical research should aim to refine antiemetic regimens and improve emetic control through the use of new antiemetic and adjuvant agents.

Ondansetron. An update of its therapeutic use in chemotherapy-induced and postoperative nausea and vomiting

Ondansetron is a selective 5-HT3 receptor antagonist which has previously been reported in the Journal to be a promising new agent for use as prophylaxis against nausea and vomiting caused by chemotherapy and radiotherapy. Since the publication of this original review, further studies have been published that show ondansetron to be an effective antiemetic agent in patients receiving chemotherapy and radiotherapy. Several studies have shown ondansetron to be a more effective antiemetic agent than high-dose metoclopramide in patients with emesis induced by high- and low-dose cisplatin treatment, and noncisplatin chemotherapy-induced emesis. The drug as mono-therapy does not appear to offer any advantage over alternative therapies against delayed high-dose cisplatin-induced nausea and vomiting; however, extremely limited data suggest that ondansetron plus dexamethasone may be useful in this indication. Trials have shown combination therapy with ondansetron and dexamethasone to be significantly more effective than both ondansetron monotherapy and a standard antiemetic regimen comprising metoclopramide, dexamethasone and diphenhydramine against acute high-dose cisplatin-induced emesis. Results from a number of small scale trials suggest that ondansetron may be an effective treatment for chemotherapy-induced emesis refractory to conventional antiemetic therapy. Ondansetron also appears to be more effective against refractory emesis induced by noncisplatin chemotherapy than that induced by cisplatin chemotherapy. Several trials have shown ondansetron to be more effective than placebo as prophylaxis against postoperative nausea and vomiting; a further trial has shown single-dose ondansetron to be significantly more effective than single-dose droperidol or metoclopramide in this indication. In addition, several trials have shown ondansetron to be more effective than placebo as treatment for nausea and vomiting that has commenced postoperatively. The overall incidence of adverse events in ondansetron recipients during chemotherapy-induced emesis studies was 36%. Headache and constipation are the most common adverse events during ondansetron therapy. Thus, recent data affirms the efficacy of ondansetron in the treatment of acute chemotherapy-induced nausea and vomiting and shows it to be especially efficacious when combined with dexamethasone. It appears that the drug will also have a substantial role in the prophylaxis and treatment of postoperative nausea and vomiting.